Xerographic apparatus



June 1964 A. J. CERASANI ETAL' 3,135,179

XEROGRAPHIC APPARATUS Original Filed April 2. 195,9 6 Sheets-Sheet l k INVENTOR.

AMERICO J. CERASAN! JOSEPH J. C(gDICHINI ILLwQYLEWIS A T TORNE V June 1964 A. J. CERASANI ETAL 3,135,179

I XEROGRAPHIC APPARATUS Original Filed April 2. 1959 6 Sheets-Sheet 2 INVENTOR. AMERICO J. CERASANI JOSEPH J. CODICHINI BY MILES DAVIS WILLIAM G. LEWIS ATTORNEY A. J. CERASANI ETAL 3,135,179

XEROGRAPHIC APPARATUS June 2, 1964 6 Sheets-Sheet 3 Original Filed April 2.

-v at 02-0510 O7ZWOLXH Mb bk Nb INVENTOR. AMERICO J. CERASANI JOSEPH J. CODICHINI J1me 1964 A. J. CERASANI' ETAL 3,135,179

XEROGRAPHIC APPARATUS Original Filed April 2'. 1959 6 Sheets-Sheet 4 INVENTOR. AMERICO J. CERASANI JOSEPH J. CODICHINI BY MILES DAVIS WILLIAM G. LEWIS A 7' TORNE Y June 2, 1964 A. J. CERASANI ETAL 3,135,179

XEROGRAPHIC APPARATUS Origin al Filed April 2. 1959 6 Sheets-Shet 5 INVENTOR. AMERICO J. CERASANI JOSEPH J. CODICHINI BY MILES DAVIS WILLIAM G. LEWIS M 44 T TOIPNEY June 2, 1964 Original Filed April 2 A. J. CERASANI ETAL 3,135,179

XEROGRAPHIC APPARATUS 6 Sheets-Sheet 6 INVBNTOR. AMERICO J. CERASANI JOSEPH J. CODICHINI BY MILES DAVIS WILLIAM G. LEWiS M ATTORNEY United States Patent 4 Claims. (Cl. 951.7)

This invention relates to improvements in xerographic reproduction apparatus and particularly to improved apparatus for xerographically recording the relative location of the leading and trailing edge of original copy being scanned and to record a control pattern indicative of the absence of original copy in the scanning system. This is a divisional application of our copending application S.N. 803,800, filed April 2, 1959.

In the process of xerography, for example, as disclosed in Carlson Patent 2,297,691, issued October 6, 1942, a xerographic plate comprising a layer of photoconductive insulating material on a conductive backing is given a uniform electric charge over its surface and is then exposed to the subject matter to be reproduced, usually by conventional projection techniques. This exposure discharges the plate areas in accordance with the radiation intensity that reaches them, and thereby creates an electrostatic latent image on or in the photoconductive layer. Development of the latent image is effected with an electrostatically charged, finely divided material such as an electroscopic powder that is brought into surface contact with the photoconductive layer and is held thereon electrostatically in a pattern corresponding to the electrostatic later image. Thereafter, the developed xerographic powder image is usually transferred to a support surface to which it may be fixed by any suitable means.

It is the practice on automatic xerographic printers of types such as disclosed in copending application S.N. 796,561, entitled Xerographic Reproducing Apparatus, filed March 2, 1959, in the name of Sten R. Iohanson, now Patent No. 3,049,968, to operate a continuously moving paper web support surface from a supply roll to takeup roll inbetween which xerographic reproductions are printed thereon. Since the original from which the reproduction is formed, may vary in dimension, can be reproduced by the xerographic apparatus. in magnified relation, or can be fed to the xerographic apparatus in untimed relation, a wide variance of spacing between successive prints may result. Blank paper occurring on the web between xerographic prints, exclusive of border width for the prints, is scrap for disposal. Since it is the usual practice to move the paper web at a constant rate of approximately 20 feet per minute (4 inches per second), a continued absence of reproduction causes a sizable accumulation of scrap paper on the take-up roll; as, for example, one minutes hesitation on the part of a human operator between feeding successive originals to the apparatus effects approximately 20 feet of scrap paper., On the other hand, accurately timed successive feeding of originals for ll /z-inch reproductions results in approximately 20 xerographically printed reproductions in the same web length.

Heretofore, the usual practice has been to periodically remove the takeup roll with the paper web wound thereon to another location whereat the paper was unwound and with a manually operative cutter, cut the web so as to effect an approximate border on the leading and trailing edge of each xerographic print. Scrap resulting therefrom was then disposed of. By these former cutting means, considerable delay was incurred in effecting availability of the xerographic reproduction and furthermore Patented June 2, 1964 required the services of additional personnel employed for this specific function.

Because of the variable occurrence of the cut on the moving web, a cutter mechanism to be effective must be responsive to a reference means on the web. In order for the cutter to respond in spaced relation to the reproduction the reference means must emanate from relation of the original to be reproduced whereby this relation is carried forth to the reproduction on the support surface. When, as here, it is intended to cut the web in relation to both the leading and trailing edge of a reproduction, the reference means must be associated with its respective edge and be distinguishable in order that the cutter be made to respond accordingly, that is, to cut the web in advance of a leading edge and after a trailing edge.

Because of the unwieldly length of scrap that might otherwise accumulate, it is also desirable to simulate reference means on scrap paper at regulated intervals in the absence of xerographic reproductions to which the cutter responds to cut the scrap into prescribed lengths. Since, in the direction of movement, the portion of web following the trailing edge of a reproduction constitutes scrap, Whereas the portion of web following the leading edge of a reproduction constitutes a xerographic print, association of reference with the respective cut permits operation of apparatus to separate scrap and reproductions. Therefore, the simulated reference means on scrap paper is distinguishable by the cutter mechanism similarly as a trailing edge. Also, the situation occasionally occurs with untimed feeding where two or more originals are fed in too close succession, i.e., where the leading edge of a follower original is too closely spaced to the trailing edge of the previous leading original. In such a situation, a minimum or insufficient border width is available for both reproductions such that only one cut is possible and because both are reproductions the reference means is to be distinguished by the cutter mechanism as a leading edge to effect proper separation and disposition of both.

It is important, therefore, in the combination of situations mentioned above, that a cutter be responsive to a reference means, that the means be effective to distinguish between leading and trailing edges and between xerographic reproduction and scrap and have means of taking into account the close spacing of successive reproductions.

The principal object of this invention is to improve xerographic reproduction apparatus for recording the location of the leading and trailing edge of original copy to be reproduced.

A further object of this invention is to improve xerographic recording apparatus to provide a predetermined control pattern in the absence of original copy.

It is a further object of this invention to form electrostatic latent image control patterns on a photoconductive surface in spaced relation to electrostatic latent images of copy to be reproduced.

It is a further object of this invention to form reference control patterns on a support surface in spaced relation to xerographic reproductions thereon.

These and other objects of the invention are attained by means of a photosensitive device and a light source separated by the passage of original copy into the machine and a light source positioned adjacent to the photoconductive surface of the xerographio machine to discharge the electrostatic charge on the photoconductive surface in response to signals received from the photosensitive device.

For a better understanding of the invention as well as other objects and further features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, wherein: I

FIG. 1 is a schematic side elevation of an automatic xerographic printer employing the apparatus of the invention;

FIG. 2 is an isometric view of the detection apparatus of the invention over which the transport means of the xerographic unit moves an original to be reproduced;

FIG. 3 is an isometric view of the exposure slit and marking apparatus of the invention for forming electrostatic latent image control patterns on a xerographic drum;

FIG; 4 is a developed surface of a xerographic drum through the cycle of charging, exposing, developing, transferring and cleaning;

FIG. 5 is a sectional view taken substantially on the line 55 of FIG. 4 illustrating the marker apparatus of the invention in relation to a xerographic drum;

FIG. 6 is an isometric view of the drive assembly and the reference scan apparatus taken from the opposite side of FIG. 1;

FIG. 7 is a sectional isometric view taken through the scan apparatus illustrated in FIG. 6;

FIG. 8 is an exploded isometric view taken from the opposite side of FIG. 1 illustrating the relation of the knife assembly and the scrap deflector; and

FIG. 9 is a wiring diagram.

Referring to FIG. 1, the paper cutter assembly of the invention, generally designated as 1, is shown in operative relation to a xerographic unit, generally designated as 2, which includes a xerographic plate in the form of drum 10 mounted in suitable bearings in the frame of the machine and is rotative at constant rate by motor 11. The drum comprises a photoconductive surface 12 on a conductive backing that is sensitized prior to exposure by means of a screened corona charging device 13, which may be of the type disclosed in Walkup Patent 2,777,957, that is energized from a suitable high potential source.

Exposure of the drum to the light image discharges the photoconductive layer in the areas struck by light, whereby there remains on the drum an electrostatic latent image corresponding to the light image projected. To project an opaque original onto surface 12, projection apparatus 3 is employed which may be of a type disclosed in above-cited copending application entitled Xerographic Reproducing Apparatus. An original to be reproduced is manually fed from support tray 14 onto endless belts 15 which are continually moved at constant rate proportional to the rate of moving web 40 by drive motor 16. As an original moves on the belts, it passes under glass 17 whereat an optical path is established from which the image on the original is reflected from mirror 22, thence through an objective lens 23 to mirror 24 through variable width exposure slit 25 so as to be exposed normal to a first axial portion of surface 12. Lamp 26 serves to illuminate the original under glass 17 and also serves to emit light to copy detection device 51 in the absence of originals to be reproduced as described below.

For controlling exposure, the aperture width of exposure slit 25 (see also FIG. 3) can be varied by dial 93 having a pointer 94 which indicates the width opening from scale 86 inscribed on the side wall of support 84. Dial 93 is secured to shaft 95 which is rotatably supported in bearing means 96. Also secured to 95 is pinion 97 meshing with gear 98 secured to rotatable shaft 99 which is an extension of support bar 143 and to which leaf 144 is secured. Gear 98 meshes with gear 145 secured to rotatable shaft 146 which is an extension of support bar 147 and to which leaf 148 is secured. Rotation of dial 93 thereby varies the aperture width of slit 25.

After exposure the image is developed by developing apparatus 27, which may be of the type disclosed in copending application S.N. 393,058, filed November 19, 1953, now abandoned, in the names of Mayo et al., in which a two-component developer material 28, which may be of a type disclosed in Walkup Patent 2,638,416, is cascaded over the drum surface. The developer material is stored at the bottom of housing 29 wherefrom conveyor 30, driven by motor 31, scoops the material and releases it over chute 37 permitting it to slide down and cascade over electrostatic latent image 76 (see FIG. 4) forming thereon a powder image 89. As toner component of material 28 is consumed, it is replenished from dispenser bottle 38 at a rate controlled by variable adjustment 39. After developing, the powder image is electrostatically transferred to a paper web support surface 40 by means of a second corona generating device 42 similar to corona generating device 13 mentioned above.

The support surface is obtained from supply spool 41 and is fed over suitable guide and tensioning rolls and directed into surface contact with the drum in the immediate vicinity of generating device 42. After transfer, the supported surface is separated from the drum surface and guided through a suitable heat fuser 43, which may be of a type disclosed in Crumrine et al. Patent 2,852,651 whereby the powder image is permanently aflixed to the support surface. Subsequent to the transfer of the image, residual image 77 on surface 12 is removed by brush cleaning with brushes 44 driven by motor 45. Web 40 then proceeds through cutter 1 as described below.

For detection of reference points on original copy and for effecting a first electrostatic latent image control pattern 75 on surface 12 therefrom, copy detection device 51 (see FIGS. 2, 3, 4 and 5) has a member 53 with a triangular slit 52 arranged between adjacent belts 15 and below glass 17 with the top surface of 53 substantially horizontal. In the absence of original copy transporting on belts 15, the light emitted from lamp 26 forms an illumination path to photocell 59 by reflecting light from inclined mirror surface 54 down through slot 56 of enclosure 58. Light thereby transmitted is realized by light-sensitive photocell 59 housed in enclosure 60, which is characterized by emitting a variable electrical signal on the realization of light wherein the magnitude of the signal varies in accordance with the intensity of illumination realized. In the preferred arrangement, the signal emitted decreases in order of magnitude when there is an obstruction of the illumination path, and increases in order of magnitude when no obstruction exists. As original copy moves on belts 15 at least a portion thereof effects a temporary obstruction of the illumination path causing cell 59 to emit discrete changes in signal output at the incipience of obstruction and unobstruction.

Electrostatic latent image control patterns 75 are formed on a second axial portion of surface 12. To produce the pattern, marker assembly 67 is operated by the detection device 51. The marker assembly includes lamps 68, 69 and 70, each enclosed in housings 64, 65 and 66, respectively, secured to support bracket 71 in turn slidably secured on a rail portion 72 of marker support frame 73. Each of the lamps are in spaced relation to surface 12 and are staggered along the axial length of the drum so that each emits a narrow light beam through apertures of their respective housing wherein the beam emitted by lamp is on a peripheral path of surface 12 substantially between thebeams of 68 and 69 (see FIG. 5). Lamps 68 and 69 are continuously illuminated, whereas lamp 70 is illuminated when the electric circuit components shown in FIG. 9 react in response to the proper order of signal change emitted by photocell 59 or when energized by other circuit means in the absence of originals to be reproduced, as described below. When all of the lamps are simultaneously illuminated they effect a dissipation of electrostatic charge in a peripheral band on the second axial drum portion. However, with lamp 70 extinguished, a narrow band on surface 12 normally dissipated by the illumination effect of lamp 70 retains its electrostatic charge and subsequently is developed by apparatus 27 are hereinbefore described (see FIG. 4). By alternate operation of lamp 70 at variable frequency of operation and duration dependent upon the obstruction period effected by the moving copy, an electrostatic latent image control pattern 75 is formed on surface 12 in spaced relation to electrostatic latent image 76 corresponding in spaced relation to reference points on theoriginal having caused obstruction and unobstruction of the illumination path.

As may be more readily seen in FIG. 4, where the obstruction and unobstruction of the illumination path has been caused by the leading and trailing edges, respectively, of copy to be reproduced, the electrostatic latent image control pattern 75 thus formed bears a spaced relation to the edge of electrostatic latent image 76. It may also be seen that, in the preferred manner of the invention, the successive peripheral line charges which constitute control pattern 75 occur in the direction of drum rotation between successive electrostatic latent images commencing with the trailing edge of one image and terminating with the leading edge of the succeeding image.

To effect lateral positioning of the control pattern in relation to the edge of drum (see FIG. 3), control knob 79 is secured to the end of rotatable lead screw 81 and has a pointer 80 integral thereof by which the relative lateral position of marker assembly 67 is indicated from scale 87. Lead screw 81 is supported in suitable bearing means 82 and 83 of stationary supports 84 and 85, respectively, whereby lead screw 81 engages bracket 71, such that on rotation of knob 79 it effects lateral movement of bracket 71 and the lamps secured thereto.

In addition to forming a first electrostatic latent image control pattern in spaced relation to an electrostatic latent image of copy to be reproduced, it is desirable, in the absence of copy to be reproduced, to effect a second electrostatic latent image control pattern since the portion of web 40 which will contact that portion of the drum will in its entirety constitute scrap. The second control pattern so established forms a signal to which a cutter responsively operative therefrom cuts the scrap into prescribed lengths. The components for effecting this second control pattern are more particularly described in the operational sequence to follow herein, but, in general, is accomplished by electric circuit means which illuminate lamps 70 in the absence of original copy, at predetermined frequency of operation and for a predetermined period of operation. 1

Another situation frequently occurs wherein two successive originals are too closely spaced, i.e. the leading edge of a following original is within a prescribed minimum distance of the trailing edge of the leading original and to which the cutter must effect proper response. In this instance if obstruction of the illumination path were relied on, the control pattern effected would be too short in length for subsequent detection and for that reason electric circuit means, as are more described in the operational sequence below, precludes less than a minimum extinguishment period of lamp 70 so as to result in pattern mark 90 on web 40 of at least /z-inch in length.

By the marker apparatus thus described electrostatic latent image control patterns are formed on a Xerographic plate which subsequently are developed and transferred to a support surface and translated therefrom as a signal to effect subsequent cutter operation. Whereas the signal produced is described herein with particular reference to effect operation of a cutter apparatus, it is apparent that the marker apparatus could be employed to effect marking signals for other purposes, as, for example, to fold, punch, or other related operations in reference to a point on the web, or xerographic reproduction. Furthermore, although particular emphasis is placed on effecting control patterns in spaced relation to the leading and trailing edges of xerographic reproductions, variations in apparatus arrangement would permit effecting control patterns in any relation thereto.

For cutting the web, the cutter is supported on frame 101 (see FIGS. 6, 7 and 8) having side supports 102 and 103 and bottom support 104. Web 40 is continuously drawn from supply roll 41 and advanced through the paper cutter by the motive force furnished from motor 105. The force therefrom is transmitted through speed reducer 106 to shaft 107 secured thereto thence to pulley 108 secured thereon. Nonslip belt 109 transmits the motion therefrom to pulley 111, secured to shaft 113, which is rotatably secured to bearing means 114 of side bracket 115 supported from side wall 102. Also secured to shaft 113 is gear 121 which meshes with gear 122 secured to rotatable shaft 123 supported in suitable bearing means of side walls 102 and 103. This effects driving of pulley 124, also secured to shaft 123, and wherefrom belt 125 transmits the driving force to pulley 125 secured to rotatable shaft 127 supported in suitable bearing means 128 and 129 and to which is secured platen rollers 130. The web passes over idler roller and then between rollers 137 and 138, of which roller 137, being secured on shaft 123 is rotative therewith. This frictionally drives roller 138 secured on rotatable shaft 139 and supported at opposite ends in bearing means 140 of pivot supports 141 (one shown) which are pivotally secured to side support 102 and 103 by pins 142. Roller 138 is urged to frictionally engage against roller 137 by the resilient spring action of springs 149 (one shown) secured between 104 and 141. For threading purposes, 138 can be spaced away from 137 by the action of cams 150 (one shown) when rotating handle 151 is secured to shaft 152 so that the rearward end of each 141 depresses against springs 149, lowering roller 138. There from web 40 when passing between horizontal guides 153 and 154 is moved by platen roller 130 thereagainst. The pressure of 130 applied on Web 40 is adjustable by rotation of handle 155 secured to shaft 156 such that pinion 157 also secured thereon and engaging rack 158 effects a raising or lowering of shaft 127.

As the web passes below detector means 167 the area thereof on which pattern marks 90 appear is illuminated by side lights 168 and 169. At the incipient detection of a leading edge of mark 90 passing into view under opening 170 of housing 178 it is reflected from mirror 171 through lens 172 held by retainer ring 179 into tube 173 to photocell 174 which immediately emits a discrete change in electrical signal through electric circuit means shown in FIG. 9. which constitutes a trailing edge signal. At the incipient detection of the mark passing out from under opening 170, another discrete change in electrical signal is emitted by 174 constituting a leading edge signal. Detector means 167 is supported in relation to the web 40 in block 176 supported by shaft in turn secured at opposite end in stationary bracket 177.

As the web emerges from between guides 153 and 154 it moves between knife member 184 in ineffective position and bed plate 185 of the knife assembly generally designated as 183 (see FIG. 8). The table plate 191 is secured by bolts to shock support plate 188 secured to support walls 102 and 103 of support frame 101. Secured between table plate 191 and the shock support plate are resilient shock mounts 192 which absorb vibration induced by cutter operation. Solenoids 197 and 198 are each mounted on table plate 191 with their plunger elements secured to journal supports 201 and 202, respectively. Shaft 203 secured in and between journals 201 and 202 is rotatably extended through bearings 207 of yoke 204. At the forward end of 204, as viewed on FIG.

8, rotatable pin 209 supports bracket 208 which in turn supports knife member 184. Rear support bracket 210 has a rotatable pin 215 extending through it to maintain the rear of 204 substantially horizontal as solenoids 197 and 198 are actuated to descent knife 184. Bolt 216, extending vertically through 204, on its descent opens microswitch normally-closed contacts lLS-l and 1LS-2. As knife member 184 descends, its rearmost edge is maintained slidably in contact against bed plate 185 by rollers 217 and 218 each rotatably secured to a pivot arm 219, in turn pivotally secured by pins 220 to side brackets 221 supported from the bed plate. Bolt 222, secured between leaf spring 223 and 219 urges the rollers firmly against the knife. For dampening the end of the descending stroke, cylinder 206 includes a rubber plug (not shown) which is compressed at the end of stroke by a piston 211 and adjustment knob 205 permits variable setting of the stroke.

After the knife has descended to cut the web, the circuit ofsolenoids 197 and 198 are de-energized as is described in the operational sequence below, and springs 224 and 225 secured at their upper end to respective brackets 226 and 227 and at their lower end to the knife immediate- 1y hoist the knife restoring it to ineffective position established by stop blocks 234 and 235.

After cutting the web, it is desired to separate the reproduction from scrap. For effecting the separation, scrap deflector assembly generally designated as 238 is secured to the knife assembly by means of bifurcated support brackets 239 and 240 such that xerographic reproductions are sorted into document bin 241 and scrap paper accumulates in scrap bin 242. Platen roller 247 is secured to shaft 248 which is rotatably supported in suitable bearing means of supports 239 and 240 and is rotated at constant rate by pulley 249 secured thereto and driven by belt 250 driven by pulley 251 secured on shaft 127 (FIG. 6). Wheel rollers 252 are secured on shaft 253 which is rotatably supported in bearing means of supports 239 and 240 wherein rollers 252 are rotated by the frictional action thereagainst of platen roller 247.

Deflector 259 is mounted so as to be pivoted on shaft 248 and is secured at its lower end by pin 258 to lateral arm 260 in turn secured to plunger 261 of solenoid 262. Energizing of the solenoid 262 moves arm 260 so as to partially rotate deflector 259 in a manner obstructing entrance of web cuttings between rollers 247 and 252 as to deflect them to scrap bin 242. With solenoid 262 deenergized, spring 263 retracts arm 260 and the deflector as to render the deflector in a horizontal plane to guide reproductions thereover into and between rollers 247 and 252 emerging into document bin 241.

In operation, all the components of xerographic unit 2 are operative. Corona generating device 13 is continually applying a uniform electrostatic charge on surface 12 and in the absence of copy a first axial portion thereof is substantially dissipated by the exposure of continuous light from lamp 26 being reflected from mirror 22 to lens 23, mirror 24 and through aperture 25. Developing apparatus 27 is continually cascading powder 28 over surface 12 and web 40 is continuously moved between corona generating device 42 and surface 12, through fuser 43 and through cutter assembly 1 as aforesaid. Lamps 68 and 69 are illuminated and photocell 59 realizes an intense illumination from lamp 26.

Referring to FIG. 9, positive rectified direct current is obtained from the part of the circuit generally outlined as 267 and negative rectified direct current is obtained from the part of the circuit generally designated as 268. Switches S1, S-2, S-3 and 84 are selectively set to coincide at any of five optional positions whereby the first position is off and the cutter apparatus 1 is deenergized. In the remaining switch positions, the cutter apparatus responds to effect operation as (1) cut on leading and trailing edges of copy and operate scrap deflect, (2) cut on leading edge only, (3) cut on trailing edge only, and (4) cut on leading and trailing edge only. For discussion purposes, it is assumed that all of the switches have been set to effect cutting on the leading and trailing edge of xerographic reproductions and also operate the scrap deflector assembly 238. Referring therefore to all figures, copy to be reproduced is first fed from support tray 14 onto moving belts 15. As the copy is moved thereon the leading edge of copy encroaches on slit 52 such that when the leading edge effects an obstruction of the illumination path between lamp 26 and detection device 51, photocell 59 realizing the decrease in illumination, effects a discrete change in electrical signal activating pentode V-5 to a bias below cut-off so as to de-energize relay 1CR. This has the effect of de-energizing relay 8CR from contact 1CR-1 and permitting normally closed contact 8CR to close energizing lamp 70. After exposure of the original at the instant the trailing edge of the copy has passed over slit 52 so as to re-admit light from lamp 26 to cell 59, the discrete change of signal emitted by photocell 59 activates the grid of pentode V-5 above cutoff, energizing relay 1CR and energizing relay 8CR therefrom so as to effect opening of normally closed contact 8CR and extinguishing lamp 70. While lamp 70 is extinguished a peripheral path on a second axial portion of surface 12 between the illumination of lamps 68 and 69 retains its electrostatic charge. As succeeding originals are fed into belts 15 at a rate between each original in excess of a prescribed minimum time, each leading edge in obstructing the illumination path from lamp 26 to photocell 59 again effects energizing of lamp 70 so as to commence dissipating the path of electrical charge affected by its illumination. The alternating operation of lamp 70 effects an electrostatic latent image control pattern 75 commencing and terminating in spaced relation on surface 12 to the trailing and leading edge respectively of successive electrostatic latent images 76. These latent images and latent image control patterns are then xerographically developed, transferred and fixed in the same spaced relation onto support web 40 as aforesaid.

Since mark 90, which constitutes control pattern, is intended as a signal from which a subsequent operation is dependent, the mark must be of sufficient length for its detection. When successive originals are closely spaced such that less than a minimum mark would be otherwise effected between the trailing edge of the leader print and the leading edge of the follower print, relay SCR which has been selected having a characteristic release time of approximately /8 second delays energizing of lamp 70 for second. On a web moving at the rate of 4 inches per second this produces a minimum pattern mark thereon of /2 in. in length.

In the event there is a prolonged absence of originals supplied to the xerographic apparatus for reproduction while it is operative, the web consumed constitutes scrap and it is desirable to effect a pattern mark from which a cutter in response thereto cuts the web into prescribed scrap lengths. With each energizing of relay 1CR (absence of original) relay 7CR is" energized in addition to relay 8CR. However, relay 7CR is characterized by an operating delay of approximately 2 seconds so as to permit effecting a pattern mark of approximately 8 inches before the normally open contacts 7CR-2 energize lamp 70. When relay 7CR becomes operative, capacitor 0-11 is discharged so as to release 7CR in its charcateristic release time of approximately A; second, thereby energizing lamp 70 for second and effecting /2 inch interruption of pattern mark. With a continued absence of originals, this cycle is repeated effecting 8 inch bordermarks and /2 inch interruptions. In the event copy to be reproduced are fed to the apparatus in the interim, the illumination path obstruction effects de-energizing relay 10R and consequently relay 7CR. After emerging from the xerographic apparatus 2, web 40, hearing xerographically reproduced image 91 and control pattern mark 90, moves into paper cutter assembly 1. The surface area on web 40 occupied by the xerographic control pattern mark 90 is continually illuminated by lamps 168 and 169, and at the incipience of a pattern mark detection or detection of its termination sensed by detector means 167, a discrete change in electrical signal is emitted by photocell 174. On incipient detection of a border mark, or a decrease in illumination at photocell 74, the discrete change of signal emitted decreases in order of magnitude and corresponds to a trailing edge signal whereas on incipient detection of border mark termination, or increase in illumination at photocell 174, the discrete change of signal emitted increases in order of magnitude and corresponds to a leading edge signal.

On detection of a leading edge signal, the signal of 174 is transmitted through amplifier circuit 269 and differentiating circuit 270 and through triode V-7B to energize relay 3CR through normally closed contacts of 1LS-2 and 4CR-2 thereby closing contacts 3CR-1 and 3CR-2. Contact 3CR-1 closes to form a holding circuit through triode V-8B whereas 3CR2 energizes timing clutch 273 of timer 274 to start the timing cycle. When timer 274, having a preset time delay, energizes, contacts 1TR-2 and 1TR-3, relay 4CR and solenoids 197 and 198 are simultaneously operated thereby opening contact 4CR-2 and descending knife 184 to cut web 40 in spaced relation to a leading edge of a xerographic reproduction. As the cutter completes its downward strike, bolt 216 strikes microswitch 1LS1 and 1LS2 opening their normally closed contacts. Since 4CR and the solenoids are energized by timer 274, the contacts of 4CR 2 are open as the knife completes its downward stroke and the holding circuit of relay 3CR is opened by opening 1LS-2 to de-energize clutch 273, restoring timer 274 to its original position, and de-energizing the solenoids and releasing relay 4CR. As solenoids 197 and 198 are de-energized, springs 224 and 225 instantly hoist the knife to ineffective position.

On detection of a trailing edge signal, a pulse applied to the grid of triode V-7A from photocell 174, is transmitted through amplifier circuit 269 and differentiating circuit 271 to effect energizing of relay 2CR through normally closed contacts of 1LS1 and 5CR2. Contact 2CR1 of relay 2CR is closed to form a holding circuit through triode VSA, whereas contact 2CR-2 energizes clutch 278 of timer 279 having a preset time delay to start the timing cycle. When timer contacts 2TR2 and 2TR3 are energized they operate relay SCR and solenoids 197 and 198 of the cutter descending the knife to cut web 40 in spaced relation to a trailing edge of a xerographic reproduction. As the cutter completes its downward stroke, bolt 216 strikes microswitch 1LS1 and ILS-2 opening their normally closed contacts. Since SCR and the solenoids are energized by timer 279, the normally closed contacts 5CR2 are open as the knife completes its downward stroke and the holding circuit of relay ZCR is opened by 1LS1 to effect release. Opening then of 2CR-2 de-energizes clutch 278 restoring timer 279 to its original position and de-energizing relay 5CR and the solenoids. As solenoids 197 and 198 are de-energized, the knife is restored to ineifective position as before. To operate scrap deflector 259, energizing of relay 5CR on the trailing edge signal energizes relay 6CR from contact SCR-l closing contact 6CR1 to hold the circuit closed while 6CR-2 is closed to energize solenoid 262 and effect scrap deflector operation. Solenoid 262 remains so energized until a leading edge signal is received energizing relay 4CR so as to open contact 4CR-1.

If, however, as stated previously, two successive originals have followed closely so as to effect a minimum Az-inch border mark between separate reproductions, it is desired to effect a single cut to separate the two reproductions whereby the cut is characaterized by a leading edge signal to result in both reproductions being disposed into document bin 241. After triode V-8A has formed a holding circuit with relay 2CR on a trailing edge signal, and a leading edge signal is received by triode V-7 B within a maximum prescribed time after V-7A has received the trailing signal, the signal of V-7B has the effect of lowering the grid bias of V-SA below cut-0E opening the holding circuit of 2CR and eliminating the trailing edge signal. If, however, the signal to V-7B has been received beyond the maximum prescribed time after receipt of signal by V-7A, the voltage across capacitor C-15 will have amassed capacity whereby the signal of V-7B imparted to triode V-8A is insufficient to lower the grid bias of V8A'below cut off.

An analogous situation occurs wherein a /z-inch interruption in pattern mark is detected in the case of extended scrap length. However, in this situation, the first signal received is equivalent to a leading edge signal and the second signal is equivalent to a trailing edge signal. Again, as before, when successive signals are received within a prescribed maximum time, it is desired to give eifect to the second signal and negate or eliminate the first thereby to effect a cut in this instance characterized by a trailing edge signal so as to operate the scrap deflector 259 in conjunction therewith and direct scrap into bin 242. After triode V-SB has formed a holding circuit with relay 3CR on a leading edge signal and then a trailing edge signal is received by triode V-7A within a maximum prescribed time after V-7B has received its signal, the signal received by V-7A has the effect of lowering the grid bias of V-SB below cut off opening the holding circuit of 3CR and eliminating the leading edge signal. However, where the signal to V-7A has been received beyond the maximum prescribed time after receipt of signal by V-7B, the voltage across capacitor C-17 will have amassed capacity whereby the signal of V-7A imparted to triode V-8B is insufficient to lower the grid bias of V-SB below cut oif.

In the preferred arrangement of the apparatus with detector means 167 located approximately two inches from knife member 184, it is readily conceivable that a trailing edge control pattern and leading edge control pattern following in relatively close succession will produce two out signals before the cutter operates. Contacts 4CR-2 and 5CR2 are operatively opened only on a leading or trailing edge out respectively to assure that each of the signals efiect their separate out.

By the apparatus thus described there is disclosed apparatus for marking and cutting a web type surface on which xerographic reproductions are formed. There is also disclosed apparatus for forming electrostatic latent image control patterns on a xerographic drum in spaced relation to an electrostatic latent image of copy to be reproduced and apparatus to cut a continuous web in spaced relation to the leading and trailing edges of a Xerographic reproduction printed thereon at variable spacing. Additional means are disclosed for eifecting separation of xerographic reproductions from scrap.

Since many changes could be made in the above construction and many apparently widely dilferent embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In a xerographic reproducing apparatus a marking device for effecting a first electrostatic latent image control pattern on a xerographic plate in spaced relation to an electrostatic latent image of copy to be reproduced and a second electrostatic latent image control pattern in the absence of copy to be reproduced wherein the xerographic apparatus includes a xerographic plate moving at constant rate, charging means for applying a uniform electrostatic charge on the plate surface, means to move copy at constant rate past an exposure means to expose the copy to a first portion of the plate surface forming an electrostatic latent image thereon; said marking device comprising in combination a light-tight enclosure having an opening therein Whereby light can enter,

a first light source arranged to project light into said opening and which is obstructed by at least a portion of copy moving between the first light source and the opening,

a light-sensitive device within said enclosure which emits discrete changes of electrical signal at the in- 1 1 cipience of obstruction and unobstruction of said light,

a second light source arranged to illuminate a second portion of the plate surface,

electric circuit means distinguishably responsive to the order of said discrete signal changes thereby to alternately illuminate and extinguish said second light source to form a first electrostatic latent image control pattern on the plate,

said electric circuit means including means in the absence of copy to be reproduced to effect periodic operation of said second light source,

said last means including means to control the frequency of said period I and means to control the duration of said operation thereby to effect a second electrostatic latent image control pattern on the plate.

2. In a xerographic reproducing apparatus a marking device for effecting successive electrostatic latent image control patterns on a xerographic plate in spaced relation to successive electrostatic latent images of copy to be reproduced wherein the xerographic apparatus includes a xerographic plate moving at constant rate, charging means for applying a uniform electrostatic charge on the plate surface, means to move copy at constant rate past an exposure means to expose copy to a first portion of the plate surface forming electrostatic latent images thereon; said marking device comprising in combination an enclosure having an opening therein whereby light can enter,

a first light source arranged to project light into said opening and which is obstructed by at least a portion of copy moving between the first light source and the opening,

a light-sensitive device within said enclosure which emits discrete changes of electrical signal at the incipience of obstruction and unobstruction of said light,

a second light source arranged to illuminate a second portion of the plate surface,

electric circuit means distinguishably responsive to the order of said discrete signal changes thereby to alternately illuminate and extinguish said second light source,

said circuit means including means to effect control patterns of minimum dimension corresponding to greater than the space between unobstruction' and obstruction caused by successive copies to be reproduced. Y

3. In a xerographic reproducing apparatus a marking device for effecting a first electrostatic latent image control pattern on a xerographic plate in spaced relation to an electrostatic latent image of copy to be reproduced and a second electrostatic latent image control pattern in the absence of copy to be reproduced wherein the xerographic apparatus includes a xerographic plate moving at constant rate, charging means for applying a uniform electrostatic charge on the plate surface, means to move copy at constant rate past an exposure means to expose the copy to a first portion of the plate surface forming an electrostatic latent image thereon; said marking device comprising in combination an enclosure having an opening therein whereby light can enter,

a first light source arranged to project light into said opening and which is obstructed by at least a portion of copy moving between the first light source'and the opening,

a light-sensitive device Within said enclosure which emits discrete changes of electrical signal at the incipience of obstruction and unobstruction of said light,

a second light source arranged to illuminate a second portion of the plate surface,

electric circuit means distinguishably responsive to the order of said discrete signal changes thereby to alternately illuminate and extingiush said second light source to form a first electrostatic latent image control pattern on the plate,

said electric circuit means including means to effect a control patern of minimum dimension corresponding to greater than the space between unobstruction and obstruction caused by successive copy to be reproduced,

and means in the absence of copy to be reproduced to effect periodic operation of second light source,

said last means including means to control the frequency of said period and means to control the duration of operation thereby to effect a second electrostatic latent image control pattern on the plate.

4. In a xerographic reproducing machine containing an image receiving web type surface, apparatus for recording the location of reproduced images on the web type surface consisting of an optical scanning system for transferring a light image of the copy being reproduced to a photoconductive surface,

means to carry original copy past said optical scanning system,

a light sensitive device positioned on one side of said carrying means and a light source positioned on the opposite side of said carrying means directed to impinge light on the light sensitive device in the absence 7 of original copy,

electrical circuitry connected to said light sensitive device and adapted to translate discrete changes in light intensity received by the light sensitive device into an electrical signal,

a photoconductive surface containing a uniform elec trostatic charge,

one or more light sources positioned adjacent the photoconductive surface and connected to said electrical circuitry whereby the light sources are intermittently illuminated by the electrical signal in response to changes in light intensity received by the light sensitive device,

and additional electrical circuitry connected to said light sources to provide a predetermined pattern of intermittent illumination in the absence of electrical signal from the light sensitive device.

References Cited in the file of this patent UNITED STATES PATENTS 2,907,985 Doersam et al. Oct. 6, 1959 2,919,170 Epstein Dec. 29, 1959 3,008,372 Willey et a1 Nov. 14, 1961 w ha, a. 

1. IN A XEROGRAPHIC REPRODUCING APPARATUS A MARKING DEVICE FOR EFFECTING A FIRST ELECTROSTATIC LATENT IMAGE CONTROL PATTERN ON A XEROGRAPHIC PLATE IN SPACED RELATION TO AN ELECTROSTATIC LATENT IMAGE OF COPY TO BE REPRODUCED AND A SECOND ELECTROSTATIC LATENT IMAGE CONTROL PATTERN IN THE ABSENCE OF COPY TO BE REPRODUCED WHEREIN THE XEROGRAPHIC APPARATUS INCLUDES A XEROGRAPHIC PLATE MOVING AT CONSTANT RATE, CHARGING MEANS FOR APPLYING A UNIFORM ELECTROSTATIC CHARGE ON THE PLATE SURFACE, MEANS TO MOVE COPY AT CONSTANT RATE PAST AN EXPOSURE MEANS TO EXPOSE THE COPY TO A FIRST PORTIN OF THE PLATE SURFCE FORMING AN ELECTROSTATIC LATENT IMAGE THEREON; SAID MARKING DEVICE COMPRISING IN COMBINATION A LIGHT-TIGHT ENCLOSURE HAVIG AN OPENING THEREIN WHEREBY LIGHT CAN ENTER, A FIRST LIGHT SOURCE ARRANGED TO PROJECT LIGHT INTO SAID OPENING AND WHICH IS OBSTRUCTED BY AT LEAST A PORTION OF COPY MOVING BETWEEN THE FIRST LIGHT SOURCE AND THE OPENING, 